/*
 * Copyright (c) 2008, Willow Garage, Inc.
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 */

/*
 * This file contains helper functions for loading images as maps.
 *
 * Author: Brian Gerkey
 */

#include <planning_ros_msgs/VoxelMap.h>
#include <stdio.h>
#include <stdlib.h>

#include <cstring>
#include <stdexcept>

// We use SDL_image to load the image from disk
#include <SDL/SDL_image.h>

// Use Bullet's Quaternion object to create one from Euler angles
//#include <LinearMath/btQuaternion.h>

//#include "map_server/image_loader.h"

// compute linear index for given map coords
#define MAP_IDX(sx, i, j) ((sx) * (j) + (i))

enum MapMode { TRINARY, SCALE, RAW };

namespace map_server {

void loadMapFromFile(planning_ros_msgs::VoxelMap& resp, const char* fname,
                     double res, bool negate, double occ_th, double free_th,
                     double* origin, MapMode mode) {
  SDL_Surface* img;

  unsigned char* pixels;
  unsigned char* p;
  unsigned char value;
  int rowstride, n_channels, avg_channels;
  unsigned int i, j;
  int k;
  double occ;
  int alpha;
  int color_sum;
  double color_avg;

  // Load the image using SDL.  If we get NULL back, the image load failed.
  if (!(img = IMG_Load(fname))) {
    std::string errmsg = std::string("failed to open image file \"") +
                         std::string(fname) + std::string("\": ") +
                         IMG_GetError();
    throw std::runtime_error(errmsg);
  }

  // Copy the image data into the map structure
  resp.dim.x = img->w;
  resp.dim.y = img->h;
  resp.dim.z = 1;
  resp.resolution = res;
  resp.origin.x = *(origin);
  resp.origin.y = *(origin + 1);
  resp.origin.z = *(origin + 2);
  // btQuaternion q;
  // setEulerZYX(yaw, pitch, roll)
  /*
           q.setEulerZYX(*(origin+2), 0, 0);
           resp->map.info.origin.orientation.x = q.x();
           resp->map.info.origin.orientation.y = q.y();
           resp->map.info.origin.orientation.z = q.z();
           resp->map.info.origin.orientation.w = q.w();
           */
  // Allocate space to hold the data
  resp.data.resize(resp.dim.x * resp.dim.y);

  // Get values that we'll need to iterate through the pixels
  rowstride = img->pitch;
  n_channels = img->format->BytesPerPixel;

  // NOTE: Trinary mode still overrides here to preserve existing behavior.
  // Alpha will be averaged in with color channels when using trinary mode.
  if (mode == TRINARY || !img->format->Amask)
    avg_channels = n_channels;
  else
    avg_channels = n_channels - 1;

  // Copy pixel data into the map structure
  pixels = (unsigned char*)(img->pixels);
  for (j = 0; j < resp.dim.y; j++) {
    for (i = 0; i < resp.dim.x; i++) {
      // Compute mean of RGB for this pixel
      p = pixels + j * rowstride + i * n_channels;
      color_sum = 0;
      for (k = 0; k < avg_channels; k++) color_sum += *(p + (k));
      color_avg = color_sum / (double)avg_channels;

      if (n_channels == 1)
        alpha = 1;
      else
        alpha = *(p + n_channels - 1);

      if (negate) color_avg = 255 - color_avg;

      if (mode == RAW) {
        value = color_avg;
        resp.data[MAP_IDX(resp.dim.x, i, resp.dim.y - j - 1)] = value;
        continue;
      }

      // If negate is true, we consider blacker pixels free, and whiter
      // pixels occupied.  Otherwise, it's vice versa.
      occ = (255 - color_avg) / 255.0;

      // Apply thresholds to RGB means to determine occupancy values for
      // map.  Note that we invert the graphics-ordering of the pixels to
      // produce a map with cell (0,0) in the lower-left corner.
      if (occ > occ_th)
        value = +100;
      else if (occ < free_th)
        value = 0;
      else if (mode == TRINARY || alpha < 1.0)
        value = -1;
      else {
        double ratio = (occ - free_th) / (occ_th - free_th);
        value = 99 * ratio;
      }

      resp.data[MAP_IDX(resp.dim.x, i, resp.dim.y - j - 1)] = value;
    }
  }

  SDL_FreeSurface(img);
}

}  // namespace map_server
